Project 1 - Parsing NASA thermodynamic data

Aim ;

Write a code in Matlab to parse the NASA thermodynamic data file and their calculate thermodynamic properties.

Objective ;

1. Write a function that extracts the 14 co-efficients and calculation the enthalpy, entropy and specific heat for all the species in the data file.

2. Calculate the molecular weight of each species and display it in command window.

3. Plot the Cp,Enthalpy and Entropy for the local temperature range (low temperature : high temperature) specific for each species.

4. Save the plots as images with appropriate names and dump them in separate folders for each species with suitable name. All these should be generated automatically.

5. The main program that you will submit will just take the "THERMO.dat" file as an input and generate Cp,H and S plots.

6. Write a detailed report.

7. Screenshot of the window where all the folder are saved.

8. Plots for O2, N2, and Co2 species.

File parsing ;

Parsing, Syntax analysis, is the process of analyzing a string of symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal grammar. The term parsing come from latin pars(orationis), meaning part. Within computational linguistic the term is used to refer to the formal analysis bhy a computer of a sentence or other, which may also contain semantic and other information. Some parsing algorithms may generate a parse forest or list of parse trees for a syntactically anbiguous input.

Parsing a file means reading in a data stream od some sort and building an in memory model of the semantic content of that data. This aims at facilities performing some kind of transformation on the data.

NASA Thermodynamic File ;

NASA thermodynamic files which is THERMO.dat file in which there are temperature range and 53 species are given in these data and each species contains 14 coefficient and temperature ranges and we have to parse these 14 coefficient to find Specific heat, Entropy, Enthalpy using formula as:-

Where,

R = Universal Gas Constant

T = Temperature

CP = Specific heat(KJ)

S = Entropy(KJ/mol-K)

H = Enthalpy(KJ/mol)

a(i) = Coefficients where, i = 1 to 14

Specific Heat ;

The specific heat is the amount of heat per unit mass required to raise the temperature by one degree celsius. The relationship between heat and temperature change is usually expressed in the form shown below where c is the specific heat.

Cp = R*(a1+(a2*T)+(a3*(T).^2)+(a4*(T).^3+(a5*(T).^4)

Entropy ;

Entropy the measure of a system thermal energy per unit temperature that is unavailable for doing useful work. Because work is obtained from ordered moplecular motion, the amount of entropy is also a measure of the ,molecular disorder, or randomness, of a system.

S = R*(a1.*log(T)+(a2*T)+((a3*(T).^2)/2)+((a4*(T).^3)+((a5*(T).^4)/4)+a7)

Enthalpy ;

Enthalpy, a property pf a thermodynamic system is equal to the system internal energy plus the product of its pressure and volume. In a system contained so as to prevent mass transfer, for processes at constant pressure, the heat absorbed or released equals the change in enthalpy.

H = R*T.*((a2*T)/2)+((a3*(T).^2)/3)+((a4*(T)/4)+((a5*(T).^4)/5)+((a6./T)))

Main code ;

clear all
close all 
clc

%input
R=8.314; %Gas Constant

%Reading data file
%Open file and reading THERMO.dat file
f1 = fopen('THERMO.dat','r')
get = fgetl(f1);

%Now reading temperature from this file
temp = fgetl(f1)

%spliting
s = strsplit(temp)

%converting strings cells into numbers
templow = str2num(s{2});
tempmid = str2num(s{3});
temphigh = str2num(s{4});

% Tempersture range
T = linspace(templow,temphigh,1000);

%skipping comment lines
for i=1:3
    get=fgetl(f1);
end

% Reading the species
for j=1:53
    tline=fgetl(f1);

    A=strsplit(tline,' '); %split into cell array
    species = (A{1}); %To read the name of the species

    %Converting string to number
    lowtemp = str2num(A{end-3});
    midtemp = str2num(A{end-2});
    hightemp = str2num(A{end-1});

    tline1 = fgetl(f1);  %getting next line
    a = strfind(tline1,'E');  %finding the string E

    %Finding first 7 higher and second 7 lower coefficients
    %Finding higher coeeficients
    a1 = tline1(1:a(1)+3);
    a1 = str2num(a1);
    a2 = tline1(a(1)+4:a(2)+3);
    a2 = str2num(a2);
    a3 = tline1(a(2)+4:a(3)+3);
    a3 = str2num(a3);
    a4 = tline1(a(3)+4:a(4)+3);
    a4 = str2num(a4);
    a5 = tline1(a(4)+4:a(5)+3);
    a5 = str2num(a5);

    tline2 = fgetl(f1);
    b= strfind(tline2,'E');
    a6 = tline2(1:b(1)+3);
    a6 = str2num(a6);
    a7 = tline2(b(1)+4:b(2)+3);
    a7 = str2num(a7);

    %finding lower coefficients
    a8 = tline2(b(2)+4:b(3)+3);
    a8 = str2num(a8);
    a9 = tline2(b(3)+4:b(4)+3);
    a9 = str2num(a9);
    a10 = tline2(b(4)+4:b(5)+3);
    a10 = str2num(a10);

    tline3 = fgetl(f1);
    c = strfind(tline3,'E');
    a11 = tline3(1:c(1)+3);
    a11 = str2num(a11);
    a12 = tline3(c(1)+4:c(2)+3);
    a12 = str2num(a12);
    a13 = tline3(c(2)+4:c(3)+3);
    a13 = str2num(a13);
    a14 = tline3(c(3)+4:c(4)+3);
    a14 = str2num(a14);

    %calculate specific_heat
    Cp = Specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,T,R,tempmid);

    %calculate Entropy
    S = Entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,T,R,tempmid);

    %calculate Enthalpy
    H = Enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,T,R,tempmid);

    %calculate Molecular weight of the species
    W = Molecular_weight(species);

    %writing molecular weight file
    MW_file = fopen('Molecular weight.txt','W');
    fprintf(MW_file,'Molecular weight of %s is %d',species,W);
    fclose(MW_file);   %closing the file

    %plotting Cp, H and S with Temperature
    %Saving in a folder
    mkdir(['E:/Programs/project1/',species])
    cd(['E:/Programs/project1/',species]);

    %plot 1 CP vs T
    figure(1)
    plot(T,Cp,'linewidth',2,'color','b')
    xlabel('Temperature (K)');
    ylabel('Specific Heat (KJ)');
    title(sprintf('Specific heat vs Temperature range of %s',species));
    grid on
    saveas(figure(1),'Specific Heat.jpg');
     
    %plot 2 S vs T
    figure(2)
    plot(T,S,'linewidth',2,'color','r')
    xlabel('Temperature (K)');
    ylabel('Entropy (KJ/mol-K)');
    title(sprintf('Entropy vs Temperature range of %s',species));
    grid on
    saveas(figure(2),'Entropy.jpg');

      %plot 3 Cp vs T
    figure(3)
    plot(T,H,'linewidth',2,'color','g')
    xlabel('Temperature (K)');
    ylabel('Enthalpy (KJ/mol-K)');
    title(sprintf('Enthalpy vs Temperature range of %s',species));
    grid on
    saveas(figure(3),'Enthalpy.jpg');

    cd('E:/Programs/project1')  %changing directory to original matlab path

    %Molecular weight
    W = Molecular_weight(species)
end

Main code explanation ;

1. Firstly , we will input the parameters R and we will open a file THERMO.dat file and reading this file using fopen command.

2. Then, we will read first THERMO using fgetl command and then we read temperature file and we split the temperature using strsplit command to convert this string to number using str2num command to find low, high and mid temperatures.

3. Then we will assign temperature range using linspace command. Then we run loop to skip command lines the data file using fgetl command inside the loop.

4. Now, we will run the loop to find 53 element in the data file by assigning fgetl command and then spliting into the cell array to find the species line and name then find the number of the temperature in the species line.

5. Then we read the new line. In order to read the coefficient in the data file we will first find the 'E' string using strfind command to find before and after numbers of the coefficient then we will find remaining 14 coefficient and convert them to numbers from string.

6. Out of which we will find first 7 coefficient which are for higher temperature and then second 7 coefficient which are for lower temperature.

7. Now we will specify Specific heat Cp, Entropy S, Enthalpy H functions to find these parameters using these 14 coefficients for lower and higher temperature. Then we well specify Molecular weight W function to find the molecular weight of the different species.

8. Now we write the molecular weight.txt file and fprint all the molecular weights of the species. And then close the txt file using fclose command.

9. Now we change the directory using cd command and then creating directory folder where we have to save our files using mkdir command and then we will change the directory to this created folder.

10. Now, we will plot Specific heat, Entropy and Enthalpy with the temperature for different species. We will use scanf command species title.

11. Then we will use saveas command to save the plots of different species in the directory folder. Now we will change the directory to which our main code file runs in the MATLAB.

Function code ;

Specific heat Function;

function Cp = Specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,T,R,tempmid)

%calculating specific heat
%calculating specific heat higher and lower temperature respectively.
 if (T <= tempmid)
     Cp = R*(a8 + (a9*T)+(a10*(T).^2)+(a11*(T).^3)+(a12*(T).^4));
 else
     Cp = R*(a1 + (a2*T)+(a3*(T).^3)+(a5*(T).^4));
 end
end

Enthalpy Function ;

function H = Enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,T,R,tempmid)

%calculating enthalpy
%calculating enthalpy for high and temperature respectively.

if (T <= tempmid)
    H = R*T.*(a8 + ((a9*T)/2) + ((a10*(T).^2)/3) + ((a11*(T).^3)/4) + ((a12*(T).^4)/5) + ((a13./T)));
else
    H = R*T.*(a1 + ((a2*T)/2) + ((a3*(T).^2)/3) + ((a4*(T).^3)/4) + ((a5*(T).^4)/5) + ((a6./T)));
end
end

Entropy Function;

function S = Entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,T,R,tempmid)

%claculating entropy
%calculating entropy for higher and lower temperature respectively.

if (T <= tempmid)
    S = R*(a8.*log(T) + (a9*T) + ((a10*(T).^2)/2)+((a11*(T).^3)/3)+((a12*(T).^4)/4)+a14);
else
    S = R*(a1.*log(T) + (a2*T) + ((a3*(T).^2)/2)+((a4*(T).^3)/3)+((a5*(T).^4)/4)+a7);
end
end

Function code explanation ;

1. Now we will find the specific heat by creating specific heat ,entropy, enthalpy function and assigning its related formula coefficient from 14 coefficients, Gas constant, Temperature and mid temperture.

2. Now we will create an condition using if loop and make the temperature less than and equal to mid temperature less than and equal to mid temperature coefficient in the formula.

3. Then we will use else condition to specify coefficient of higher temprature coefficient in the formula.

4. Then end the loop and function to calculate specific heat, entropy, enthalpy.

Function code molecular weight;

function W = Molecular_weight(species)

%Defining atomic name of the species
atomic_name = ['H','C','O','Ar'];

%Defining atomic masses of main species
atomic_weight = [1.008 12.011 15.999 14.007 39.948];

%Molecular weight starting range 
W = 0;

%Loop run to the length of the species and atomic_name
for i=1:length(species)
    for j=1:length(atomic_name)
        if strcmp(species(i), atomic_name(j))
            W = W + atomic_weight(j);
            position = j;
        end
    end
    n=str2num(species);

    if n>1
        W = W + atomic_weight(position)*(n-1);
    end
end
fprintf('Molecular Weight of %s :-',species);
fprintf('%f',W);
disp(' ')
end

Function molecular weight explanation ;

1. Firstly we create an Molecular_weight function W and assigning species input to that.

2. Then define the main element of all 53 species in an array atomic_name that are:- 'H","C","O","N",Ar'.

3. Then by taking above main elements we will create there atomic_weight array from any source like internet that are :- -1.008 12.011 15.999 14.007 39.948.

4. Then we will assign molecular starting range W to zero and then create an for loop condition which runs to the length of the species and an another nested for loop is created which runs to the length of the string atomic_name.

5. Then we will create an conditon using if ocndition and use strcmp command to compare the species and atomic_name strings to calculate molecular masses if by comparison both string found same then we will assign its molecular weight .

6. Now, we will string to the number using str2num command assign to n. Then we run conditon of if loop to find weather the species contains more than one element if there are more than 1 element that is n>1 then we will increment the atomic weight by the multiplication of position and n-1 to the atomic_weight array.

7. Then we will print the molecular weight using fprintf command display it using disp command.

Outputs ;

The output plot diagram and Screenshots are attached in the below option.

Conclusion ;

Therefore, we have successfully parsed the given NASA thermodynamic data file and plotted the graphs of specific heat, enthalpy, and entropy are executed clearly.